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Fair Value Measurements - Significant Unobservable Inputs Used to Value Level 3 Instruments (Details 2) $ in Thousands | 9 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2023 USD ($) $ / MMBTU $ / MWh | Dec. 31, 2022 USD ($) $ / MMBTU $ / MWh
Information regarding the entity's internally developed significant unobservable inputs used to value its level 3 instruments |  |
Assets | $ 1,503,184 | $ 1,552,870
Liabilities | 55,744 | 42,446
Level 3 |  |
Information regarding the entity's internally developed significant unobservable inputs used to value its level 3 instruments |  |
Assets | 6,825 | 26,132
Liabilities | 0 | 31,020
Level 3 | Forward Contracts | Commodity Contracts |  |
Information regarding the entity's internally developed significant unobservable inputs used to value its level 3 instruments |  |
Assets | 6,825 | 26,132
Liabilities | $ 0 | $ 31,020
Level 3 | Forward Contracts | Valuation Technique, Discounted Cash Flow | Commodity Contracts | Minimum |  |
Information regarding the entity's internally developed significant unobservable inputs used to value its level 3 instruments |  |
Electricity forward price (in usd per MWh) | $ / MWh | 37.79 | 37.79
Natural gas forward price (in usd per MMBTu) | $ / MMBTU | 0.10 | (11.81)
Level 3 | Forward Contracts | Valuation Technique, Discounted Cash Flow | Commodity Contracts | Maximum |  |
Information regarding the entity's internally developed significant unobservable inputs used to value its level 3 instruments |  |
Electricity forward price (in usd per MWh) | $ / MWh | 224.49 | 310.69
Natural gas forward price (in usd per MMBTu) | $ / MMBTU | 0.13 | 0.00
Level 3 | Forward Contracts | Valuation Technique, Discounted Cash Flow | Commodity Contracts | Weighted-Average |  |
Information regarding the entity's internally developed significant unobservable inputs used to value its level 3 instruments |  |
Electricity forward price (in usd per MWh) | $ / MWh | 121.24 | 163.92
Natural gas forward price (in usd per MMBTu) | $ / MMBTU | 0.11 | (5.08)
Level 3 | Forward Contracts | Valuation Technique, Discounted Cash Flow | Electricity | Commodity Contracts |  |
Information regarding the entity's internally developed significant unobservable inputs used to value its level 3 instruments |  |
Assets | $ 6,175 | $ 26,132
Liabilities | 0 | 1,759
Level 3 | Forward Contracts | Valuation Technique, Discounted Cash Flow | Natural Gas | Commodity Contracts |  |
Information regarding the entity's internally developed significant unobservable inputs used to value its level 3 instruments |  |
Assets | 650 | 0
Liabilities | $ 0 | $ 29,261

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